Hydraulic clutch.



O. E. CURTISS. HYDRAULIC CLUTCH.

APPLICATION FILED .TAN.13,1913.

1,104,168, Patented July 21,191L

Z SHEETS-$113131 l.

34 Inucvmw Olcwsnoc CbLuMiss G. E. GURTISS.

HYDRAULIC CLUTCH.

APPLICATION FILED JAN. 13, 1913. 1 104,168 Patented July 21, 1914.

2 SHEETS-SHEET 2.

wifncwes IuucM'ov M (Suwanee flumss UNITED STATES PATENT OFFICE. CLARENCE E. C URTISS, 0F GRAND RAPIDS, 'MICHIGAN,'ASSIGNOR OF TWO-THIRJ JS TO ROBERT B. KELLOGG, OF GRAND RAPIDS, MICHIGAN.

HYDRAULIC CLUTCH.

Specification of Letters Patent.

Patented July 21, 1914.

To all whom it may cqgcem Be-itrknown that I, CLARENCE E. Cun'rrss, a citizen of the United States of America, residing at Grand Rapids, in the county of Kent and State of Michigan, have'invented certain new and useful Improvements in Hydraulic Clutches; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it apvice which is simple, compact and durable in construction and efficient in operatlon,

and to provide-the same with various new and useful features hereinafter more. fully:

dscribed and claims.

My invention consists essentially of a stationary case, a driving shaft and'a driven shaft projecting into the case, cylinders rotating with one of said shafts and connected thereto, pistons in the cylinders connected to particularly pointed out in the the other shaft and means for controlling the l flow of fluid through the cylinders to con-j trol the movement of the pistons therein and in various features of construction, combination and arrangement, as hereinafter more fully described and particularly point-- ed out in the claims, reference being had, to i the accompanying drawings in which through the axis of a device embodying my invention and, Fig. 2 1s a transverse sectional elevation taken through the'axis of exterior thereof for the purpose of mounting the device on the frame of an automobile. The case 1 is provided with a removable head 3 to enable the'interior mechanism to be inserted and a bearing is provided in the axis of each head of the case, the driving shaft 4 being journaled in one of these bearings and the driven shaft 5 in the other bearing and both shafts projecting inside the case.

A cylindrical drum considerably smaller in diameter than the case, the ends of which engage the respective ends of the case, is rotative in said case and attached to the inner end of the driven shaft 5. This drum is pro vided with radial cylinders 7 preferably four in number as shown; these cylinders being formed integral with the drum and having their inner ends open to the interior thereof, and each cylinder provided with a piston 8.

The inner end of the driving shaft 4: is provided with two cranks 9, the throws of these cranks being located 180 degrees apart or diametrically opposite and the end of the connected to each crank and by connecting diametrically opposed pistons to opposite vcranks, as described, the side thrust of the crank shaft is eliminated and the strain on its bearings reduced to a minimum.

Each piston head is provided with an out-v ward opening check valve 11, and each cylinder head is provided with similar outward opening check valve 12 so that recip- Figure l is a sectional elevation takenrocation of the pistons in the cylinders pumps any fluid contained in the case and drum, from the interior of the drum through the cylinders and into the case. A by-pass 13 leads from the lower part of the case and communicates with a series-of ports 14 in one end of the drum (Sand a valve 15 in the bypass is adapted to be manually operated whereby said by-pass may be restricted, or wholly closed.

filled with an incompressible fluid and a reservoir 16 is provided. to contain a reserve The radial cyl- The case is intended to be completely supply of fluid by which theicase m be formed on one of the heads of the case, and communicates by a passage 17 with a series of ports 18 in one end of the drum-6. A valve 19 having swinging closures is inserted in this passage and permits a free flow of fluid from the reservoir into the interior of the drum and closes to prevent the return thereof under normal conditions. This swing closure is provided with an adjustable spring closed valve 20, which allows the fluid to pass back into the reservoir should the pressure within the drum become sufficient to overcome the tension of the spring. An automatic air vent 21 is provided in the top of the reservoir, consisting of a float 22, adjustably' mounted upon the stem of a needle valve 23.- The object of this float is to permit a free ingress and egress of air as the level of the fluid in the reservoir rises and lowers within a certain limit, and should the fluld rise in the reservoir completely filling the same, the float 22 will lift the needle valve 23 and close the vent, thus preventing the reservoir from overflowing.

An air cushion chamber 24 is provided. on the upper side of the case and communicates with the interior thereof by passages 25 and its object is to entrap a quantity of air, which owing to its compressibility, serves as a cushion to equalize the pressure of the fluid in the case and absorbs sudden shocks and excessive pressure therein. The quantity of air entrapped in'the cushion chamber may be regulated by means of an' automatic air vent 26 similar to the one in the fluid reservoir, this valve automatically opening to allow air to enter as the level of the fluid in this chamber falls and automatically closes as the float 22 is lifted by the fluid as it rises in the chamber.

During the operation of the device, it might occur that extremely high pressure is produced in the ease by overloading the clutch, said pressure being greater than the air cushion chamber is able to absorb. I have provided a relief valve 27, which will open under such high pressure and permit a portion of the fluid to pass from the case through a bypass 28 and ports 18 into the interior of the drum 6. This automatic relief valve 27 also serves as a governor valve to limit the maximum speed of the driven shaft, and is preferably of a partially balanced type. valve projects through a boss 30, which forms a bearing for a gear 31 and this gear forms-the rotating body of a centrifugal governor, which may be of any appropriate form and which is adapted to actuate the reliefvalve 27. As shown, this governor com-prises two diametrically opposite bell cranks 33 pivoted in lugs 32, which project from the face of the gear 31. The parallel arms of these bell cranks are provided with weights which have a tendency to spread The valve stem 29 of this radially by centrifugal force as they rotate. The inturned ends of these bell cranks traverse a groove in a collar 34 fixed to the outer end of the valve stem-29, and a spring 35 serves to yieldably draw the parallel arms of the bell cranks 33 together and thrust the valve 27 against the seat. The gear 31 is driven from the driven shaft 5 by a gear 36, on said shaft.

In order to prevent the flow of fluid between the adjacent ends of the drum 6 and case, I have provided metallic packing rings 37 which are let into the ends of the case and are thrust against the ends of the drum by springs 38. I also further provide annular leather packing cups 39 surrounding these rings between the case and drum. The fluid is prevented from escaping through .the shaft. bearings by appropriate stufling boxes 40. y

The operation of the device is as follows :Assuming the device to be standing still, and that the valve 15 in the by-pass is fully open to permit free flow of fluid from the case to the interior of the drum: Under these conditions, the driving shaft 4: may be started and run freely without affecting the driven shaft 5, the pistons 8 will traverse the cylinders and the fluid will be pumped from the drum into the cylinders and out into the case through the check valves 11 and 12, and thence flow to the interior of the drum through the bypass 13,'and ports 14. By partially closing the valve 15 the byass will be restricted and the passage of uid therethrough will be partially cut off and a slight pressure will be produced in the case, which will olfer a resistance to the pumping action of the pistons. This resistance causes the cylinders and drums 6 to begin to follow the rotation of the driving shaft, thus turning the driven shaft 5 which is attached to the drum. The pistons will of course, move in the cylinders only enough to displace the volume of fluid allowed to escape through .the valve 15 and thus the difference in speed between the driven and the driving shafts may be varied and controlled entirely by this valve and when the valve is fully closed, and the by-pass 1'3 entirely'cutoff, the two shafts will rotate at approximately the same speed as there is no communication between the case and the interior of the drum and the pumping action of the pistons is entirely prevented.

The case is normally completely filled with fluid and a reserve supply is contained in the fluid reservoir 16 and should any leakage occur, the case will be replenished from the reservoir through the valve 19.

In passing over rough roads, or over 0bstructions and under various conditions, there is constant variation in the resistance offered by the driving wheels, and these slight sudden changes and the small shocks are absorbed by the air in the cushion chamber 24%, which, owing to its compressibility and flexibility equalizes the fluid pressure in the case. In case of sudden exaggerated overload to the clutch caused such as by suddenly closing the valve 15 with the engine running, or by suddenly applying the brakes when the car is in motion, resulting in an excessive high pressure in the case, the valve 27 which is normally closed, will be opened by this pressure and the fluid will be allowed to pass from the case through the passage 28 and ports 18 into the interior of the drum 6 and thus the pistons will be allowed to reciprocate in the cylinders, relieving the strain between the driving and driven members. Should this rush of fluid through the Valve 27 and passage 28 into the interior of the drum be so great that a pressure would be formed in the drum, sufficient to overcome the tension of the spring of the valve 20, this fluid would pass through this valve into the fluid reservoir where it will be maintained until the pressure in the case and drum is again reduced, at which time, it

will return to the interior of the drum.

In many cases it is desirable to limit the speed of the driven shaft, consequently the speed of thecar to a certain predetermined maximum speed, regardless of excessive power orspeed of the motor; this may be attained by adjusting the tension of the spring 35 on the centrifugal governor so that the relief valve 27 will remain closed until the predetermined speed has been attained, at which time, the centrifugal force of the weights will be sufficient to overcome the tension of the spring and will raise the valve 27 from its seat, allowing the fluid to pass through the case to the interior of the drum and permitting the pistons to reciprocate thus allowing the driving shaft to rotate faster than the driven shaft.

I do not care to limit myself to the use of thisudevice in connection with automobiles, as it will be obvious that it may be used in any power transmitting shaft, but when used in connection with automobiles as herein shown, or in any line where the direction of rotation of the driven shaft must be changed without reversing the motor, it will be necessary to use some appropriate form of reverse gear to reverse the rotation of the driving shaft, this clutch acting with equal efficiency when rotated in either direction, and if desired, the functions of the driven'and driving shafts may be transposed, making the driven shaft the driving one, and vice versa; although I prefer to use the device as herein shown and described.

It is obvious that this device affords a clutch and speed changing mechanism which is effective and positive in operation and very flexible in control, it being possible to obtain any speed of the driven shaft from an idle or neutral position to a direct drive from the driving shaft.

\Vhat I claim is 1. A hydraulic clutch, comprising a stationary case, a driving shaft and a driven shaft projecting withinthe same, a chamber on one shaft, radial cylinders communicating with the said chamber, pistons in said cylinders, cranks on the other shaft and connected to the pistons, and means for controlling the flow of fluid from the case to the chamber and through the cylinders.

2. A hydraulic clutch, comprising a stationary case, a driving shaft and a driven shaft projecting within the same, a chamber provided with radial cylinders communicating with the interior thereof, and fixed to the inner end of one shaft, a piston in each of the radial cylinders, cranks on the inner end of the other shaft connected to the pistons in the cylinders, outwardly opening check valves in the piston and cylinder heads, a by-pass from the interior of the case to the interior of the drum, and a valve in the by-pass whereby it may be restricted or closed. I

3. A hydraulic clutch, comprising a fixed outer case, a driving shaft and a driven shaft, journaled in the respective ends of the case and projecting within the same, a chamber provided with radial cylinders communicating with the interior thereof, and fixed to the inner end of the one shaft, a piston in each of the said cylinders, cranks on the inner end of the other shaft and connected to the said pistons, check valves in the pistons, and cylinder heads, a by-pass from the interior of the case to the interior of the said chamber, a manually operated valve in said by-pass, a spring actuated relief valve adapted to open under excessive pressure and a passage leading from the said relief valve to the interior of. the chamber.

4. A hydraulic clutch, comprising a fixed outer case, a driving shaft and a driven shaft journaled in the respective ends of the case and projecting within the same, a chamber having radial cylinders communicating with the interior'thereof fixed on the inner end of one shaft, a piston in each of the cylinders, cranks on the inner end of the other shaft connected to the said pistons, check valves in the pistons and cylinder heads, a by-pass from the interior of the case to the interior of the chamber, a manually operated valve in said by-pass, and means for automatically controllin the speed of the driven shaft, comprising a valve opening from the case, a passage from said valve to the interior of the chamber, and a centrifugal governor adapted to control the said valve.

5. The combination with a hydraulic clutch having a fixed outer case and a rotative chamber, of a fluid reservoir mounted on the said case, and communicating with the said chamber.

6. The combination with a hydraulic clutch having a fixed outer case-and a central rotative chamber, of a fluid reservoir mounted on said fixed case, a passage from the interior of said reservoir to the interior of said chamber, a check valve in said passage to permit a flow of fluid from the reservoir to the chamber, and a spring closed valve to permit the return of fluid from the said chamber to the reservoir.

7. The combination with a hydraulic clutch having a fixed outer case and a central rotative chamber, of a fluid reservoir mounted on the said fixed outer case, a passage from the said fluid reservoir to said chamber and an automatic air vent in the top of said fluid reservoir to permit ingress and egress of air thereto, said air vent being adapted to be automatically closed to prevent the escape of fluid therethrough.

8. The combination with a hydraulic clutch having a fixed outer case containing fluid under varying pressures of an air cushion chamber mounted on the said case and communicating with the interior thereof, and an automatic air vent adapted to entrap a quantity of air in the said chamber, substantially as and for the purpose described.

In testimony whereof I aflix my signature in presence of two witnesses.

CLARENCE E. CURTISS.

Witnesses:

HAROLD O'. VAN ANTWERP, v RAY W. LANGFIELD. 

